Nghe TOEFL

🎧 Bản ghi âm

Listen to part of a lecture in a biology class. The professor is discussing animal communication. 'Today, we're going to look at a fascinating example of animal communication: the waggle dance of honeybees. When a worker bee discovers a rich source of nectar, she returns to the hive and performs a series of movements on the vertical surface of the honeycomb. This dance encodes information about the direction and distance of the food source. The direction is indicated by the angle of the dance relative to the sun's position. For instance, if the bee dances straight up, the food is directly toward the sun. If she dances to the right, the food is at a corresponding angle to the sun. The distance is communicated by the duration of the waggle phase and the number of circuits. Longer waggles indicate greater distances. Interestingly, researchers have found that bees can adjust the accuracy of their dances based on the quality of the food source. When the nectar is highly concentrated, the dance is more vigorous and precise. However, when the food source is poor, the dance may be less detailed, and sometimes bees even stop dancing altogether. This suggests that the waggle dance is not just a fixed signal, but a flexible system that reflects the forager's assessment of the resource.'